Why Unified FMT Standards Were Needed

Fecal microbiota transplantation (FMT) has evolved from an experimental procedure to a recognized treatment method over the past decade. International guidelines recommend FMT for recurrent Clostridioides difficile infection, and research demonstrates efficacy for inflammatory bowel disease, irritable bowel syndrome, and even neuropsychiatric disorders.

However, the lack of standardized methodology led to significant variability in outcomes between clinics and studies. This made it difficult to assess the true efficacy of FMT and hindered its adoption in clinical practice.

In 2020, four leading Chinese medical organizations joined forces to create the first national guidelines for FMT standardization. The foundation was data from the Intestinal Microecology Diagnosis and Treatment Center at Shanghai Tenth People's Hospital (affiliated with Tongji University): 3,575 patients and over 60,000 FMT procedures since 2012. This represents one of the largest clinical FMT experiences in the world.

The guidelines established 13 standards—from laboratory requirements to cure criteria. Let's examine the key provisions.

Super Donors: Who They Are and Why They Matter

FMT success largely depends on the quality of donor material. Chinese experts developed a six-dimensional donor assessment system.

Six Dimensions for Standard Donor Selection:

1. Physiology — age 18–30 years, BMI 18.5–23.9 kg/m², negative tests for hepatitis, HIV, cytomegalovirus, parasites, C. difficile, multidrug resistance genes
2. Psychology — normal scores on depression (SDS), anxiety (SAS), and sleep quality (PSQI) scales
3. Personal History — no chronic diseases, no antibiotics for 3 months, no vaccinations for 6 months
4. Stability — re-screening every 2 months, 16S rDNA sequencing of each donation
5. Consistency — regular donation at least twice weekly, minimum 100g per donation
6. Dietary Tolerance — ability to follow a diet excluding recipient's allergens for 5 days before donation

Super Donor Criteria

Not all donors are equally effective. Data analysis revealed a category of "super donors"—those whose material achieves ≥75% efficacy in 50 or more patients.

An unexpected discovery was the correlation between efficacy and personality traits. Researchers used the Chinese version of the Big Five model and found that super donors have:

• Extraversion >20 points
• Openness >20 points
• Neuroticism <15 points

The link between personality traits and gut microbiome composition has been confirmed by other studies. Extroverts and open individuals typically lead more active lifestyles, have diverse diets, and maintain wide social networks—all positively affecting microbiome diversity.

Indications and Contraindications

The guidelines clearly defined who should receive FMT and who should not.

Indications

Intestinal diseases associated with dysbiosis:

• Recurrent C. difficile infection
• Inflammatory bowel disease: ulcerative colitis, Crohn's disease
• Irritable bowel syndrome
• Functional gastrointestinal disorders
• Chronic constipation

Extraintestinal diseases with intestinal symptoms:

• Autism spectrum disorder with constipation or diarrhea
• Parkinson's disease with constipation
• Atopic dermatitis with intestinal symptoms
• Depression unresponsive to standard therapy

Contraindications

1. Severe immunosuppression (neutrophils <1,500/mm³, lymphocytes <500/mm³)
2. Severe intestinal mucosal damage
3. Unidentified cause of mucosal damage
4. Fulminant colitis or toxic megacolon
5. Inability to tolerate enteral nutrition (≥50% of caloric needs)
6. Systemic inflammatory response syndrome (SIRS)
7. Extraintestinal infections requiring broad-spectrum antibiotics
8. Severe malnutrition (BMI <15, albumin <25 g/L)
9. Congenital or acquired immunodeficiencies
10. Recent immunosuppressive or cytotoxic therapy
11. Pregnancy and lactation

Dosing and Treatment Courses

Standard Dose

The experts were the first to propose measuring dose by viable bacteria count rather than fecal mass:

• Minimum dose: ≥2.5×10¹² CFU of active bacteria per procedure
• By weight: ≥30g for adults, 1g/kg body weight for children

Standard Course

One standard course includes 6 daily procedures of bacterial suspension infusion. With positive response, a consolidation course follows—6 days of capsule administration. Interval between courses is 4 weeks.

Disease-Specific Protocols

Disease	Standard Courses	Consolidation Courses
C. difficile infection	1	1
Chronic constipation	2	2
Irritable bowel syndrome	2	2
Inflammatory bowel disease	4	4
Autism spectrum disorder	2 (capsules)	4 (capsules)

Course Escalation Factors

An additional standard course is recommended for:

• Comorbidities or medications affecting microbiota
• Disease duration exceeding 5 years
• Patient age ≥65 years

Cure Criteria

The guidelines established objective efficacy criteria for each disease. General principle: clinical remission plus microbiota diversity restoration to ≥50% of donor levels.

C. difficile infection: complete symptom resolution within 8 weeks (formed stool <3 times/day), negative toxin A and B tests.

Chronic constipation: ≥3 spontaneous bowel movements per week at 8 weeks post-treatment. Stool frequency improvement ≥50% is considered partial response.

Ulcerative colitis: at 12 weeks—Mayo score 0 (remission) or Mayo ≤2 with endoscopic component ≤1 (treatment response).

Crohn's disease: at 12 weeks—CDAI <150 (remission) or CDAI reduction ≥100 (response).

Irritable bowel syndrome: absence of abdominal pain and stool disturbances for 3 consecutive months.

Autism spectrum disorder: at 12 weeks—ABC <31 and CGI-I score 1 (marked improvement) or ABC <67 with improvement in at least 2 subscales by ≥50%.

FMT Preparation and Adjunctive Therapy

Proper preparation enhances procedure efficacy. Learn more on our procedure page.

Antibiotic Preparation

Vancomycin 0.5g twice daily is prescribed 3 days before FMT to suppress pathogenic flora and create "ecological niches" for donor bacteria. Rifaximin may be used for IBS, antifungals for fungal infections.

Bowel Cleansing

24 hours before the procedure—polyethylene glycol (PEG) 2 liters to remove residual antibiotics, toxins, and pathogen spores.

Adjunctive Therapy

Probiotics and prebiotics are recommended throughout the course. Enteral nutrition for intestinal dysfunction or malnutrition. Coordination with relevant specialists for neuropsychiatric indications.

Safety and Adverse Events

FMT is generally well tolerated. Most adverse events are mild and self-limiting. Learn more on our safety page.

Adverse Event Classification

Mild (observation):

• Dizziness, weakness
• Throat discomfort (with nasointestinal delivery)
• Nausea, bloating, mild abdominal pain
• Temperature <38°C
• Diarrhea <5 times/day

Moderate (FMT suspension, symptomatic therapy):

• Vomiting
• Temperature <39°C
• Diarrhea 5–10 times/day
• Cramping abdominal pain

Severe (FMT discontinuation, intensive care):

• Temperature ≥39°C
• Diarrhea >10 times/day
• Blood in stool
• Toxic megacolon
• Signs of systemic inflammatory response

Serious Incidents

In 2019, two cases of multidrug-resistant bacterial infection following FMT were reported in the United States, one resulting in death. The cause was inadequate donor screening for drug resistance genes. This underscored the critical importance of thorough donor selection—a requirement incorporated into the Chinese guidelines.

Clinical Implications

The 2020 Chinese FMT standards represent the first attempt to systematize vast clinical experience into reproducible protocols. Key achievements:

• Introduction of the "super donor" concept with objective criteria
• Dose standardization based on viable bacteria count
• Clear course protocols for different diseases
• Measurable efficacy criteria
• Adverse event classification and management algorithms

Our clinic uses these standards as the foundation for FMT protocols, adapting them to each patient's individual characteristics.

If you're considering FMT as a treatment option, contact us for a consultation—we'll evaluate your indications and develop an optimal treatment plan.

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Source: Chinese experts consensus on standardized methodology and clinical application of fecal microbiota transplantation. Chinese Journal of Gastrointestinal Surgery, 2020. DOI: 10.3760/cma.j.cn.441530-20200420-00231